If, in the onComplete handler of an item, you call remove() on it, BulkLoader can stall. It comes from _onItemComplete being added using int.MIN_VALUE:
item.addEventListener(Event.COMPLETE, _onItemComplete, false, int.MIN_VALUE, true);
To fix it, either set the priority to int.MAX_VALUE, or update the remove() function to include:
if(allDone) {
_onAllLoaded();
}
else if ( !_isPaused )
{
// this needs to try to load a next item, because this might get called inside a
// complete handler and if it's on the last item on the open connections, it might stale
_loadNext();
}
I'm more for the latter solution, as it's already used in a number of places in the file to combat the same problem